I didn't do it, I just found the video when I had other problems.
I don't think you can get to the rocker arms with it in place. Disconnecting all power and fueling lines and exhaust and then unbolting the box from the mounts while supporting it with a jack would be required. Also the generator doesn't run with out being hooked up to the controls, which are mounted in the RV, unless you buy a spare set - at least that is what my local Cummins dealer said when pulled mine under warranty.
If you plan to pull it and do the work, you could go to your local Cummins dealer. Or search the internet for Hatz parts, as the motor is a Hatz. There are some other threads running on QD 3200 issues as well, suggest searches for QD 3200 and Hatz for more info.